When I first made this graphic, it included two unexplored worlds: Ceres and Pluto, and 2015 seemed impossibly far away.

Now here we are, and only one remains. Of course, all these places have centuries of exploration ahead, but the era of unveiling major worlds in our solar system for the first time is reaching its twilight, right before our eyes. I almost don’t want it to end.

Almost.

Some worlds of the solar system before and after they were explored by recent spacecraft.

For years, scientists exploring the Earth’s moon have benefitted from detailed, three-dimensional views of the lunar landscape. Now, it’s easier than ever for anyone to see those same 3D pictures.

The Lunar Reconnaissance Orbiter is a robotic spacecraft that circles the moon continuously, mapping the surface in gritty detail with its Narrow Angle Cameras. Sometimes, mission managers target a location for 3D imaging by sending the orbiter over the same spot twice, photographing the surface at two different angles. Those two perspectives can be combined to create a stereoscopic view.

One relatively easy way to recreate a sense of depth in those pictures is to split the images into red and cyan components. A viewer can then look at these pictures, called anaglyphs, through red-blue glasses, which have a red lens for the left eye and a blue one for the right. This sends only the correct part of the image to each eye, and the result is like magic: a picture with contours that seem to rise and fall right through the screen or the paper.

If you don’t already have some red-blue glasses, you’ll want to get a pair (they’re not too hard to come by) because the Lunar Reconnaissance Orbiter team at Arizona State University has recently assembled an entire collection of red-blue anaglyphs. See this page and search on the term “anaglyph”.

The moon’s surface is full of dramatic landscapes, and these 3D views are a fascinating way to explore them. Future robotic rovers and astronauts alike will find data like this to be a valuable guide to their expeditions. In the meantime, we can simply enjoy the incredible pictures. Here are just a few.

Hell Q is one of a group of craters on the lunar nearside, named for a Hungarian astronomer. This Lunar Reconnaissance Orbiter narrow angle shot, showing an area only about five kilometers wide, is viewable in 3D using red-blue glasses. Credit: NASA / GSFC / Arizona State University

A Lunar Reconnaissance Orbiter view of the eastern part of Thales Crater. The rugged landscape is viewable in 3D using red-blue glasses. The full crater is about 32 kilometers from rim to rim. Credit: NASA / GSFC / Arizona State University

On the edge of the moon’s Oceanus Procellarum lies the crater Krafft, which is connected to the crater Cardanus by a crater chain called Catena Krafft. The chain, partially seen here in an image from the Lunar Reconnaissance Orbiter, is about 60 kilometers long. This image is viewable in 3D using red-blue glasses. Credit: NASA / GSFC / Arizona State University

This post originally appeared as a guest blog entry on The Planetary Society site.

One year ago today, the US federal government shut down due to a budget impasse, leaving NASA’s outreach teams unable to work. So I tweeted:

In solidarity, today I’m tweeting some #ThingsNASAMightTweet if they could.

I didn’t think much about it. But what happened next was astounding. People from all over the world joined in, and by the end of the day there were dozens of posts about NASA, space exploration, and science in general bearing the #ThingsNASAMightTweet tag.

It just grew from there. Sixteen days later, my last #ThingNASAMightTweet read:

On the 16th of February, at 3:16 pm (local Mars time), a robotic spacecraft orbiting the Red Planet trained its most powerful camera on the surface. It captured an image so detailed that if someone were standing there waving you could see their shadow.

This dune field inside a crater, on the floor of an ancient river bed, is one small part of that picture. Why did NASA engineers radio commands across 60 million miles of space in order to point the multi-million-dollar spacecraft at this particular spot?

Because I told them to.

Ripples in the Valley – A field of ripples within a crater in Verde Vallis, an ancient river bed on Mars. This scene, about 500 meters across, is a small part of a high-resolution observation from the HiRISE camera aboard the Mars Reconnaissance Orbiter. NASA / JPL / University of Arizona

So how did that happen? I am not a member of the teams that manage the Mars Reconnaissance Orbiter (MRO) or the High Resolution Imaging Science Experiment (HiRISE) camera that took this image. I’m not even a scientist or an engineer. How was I able to play a role in selecting this target?

The HiRISE team runs what I think is one of the most compelling programs in all of space exploration. It’s called HiWish, and it allows anyone to suggest a spot on Mars where the HiRISE instrument should take an image. All it takes is a visit to the HiWish web site, where you can browse a map of the planet to see which areas have already been observed and which are still ripe for exploration.

After selecting a target, and entering a brief explanation of why that particular spot interests you, you can submit your suggestion. If it’s accepted, you will have personally helped select one of the next places on Mars that we see, often for the first time ever, at the extremely high resolution of HiRISE images. The results of a HiWish can be pretty spectacular.

Not surprisingly, there are thousands of suggestions in the queue at any one time, and not all of them can be pursued. A spacecraft like MRO is a rare and powerful asset, and teams of scientists and engineers work in tandem to carefully plan the robotic explorer’s every move. What can you do to raise your own suggestion’s odds?

According to Sarah Milkovich, HiRISE investigation scientist, the key is to provide a compelling rationale. If you’re asking for yet another shot of the famous (infamous?) “face” in Cydonia, Dr. Milkovich says, well, that’s been done. She says what the team is looking for are previously un-imaged areas, or places that merit re-examination for specific reasons, and/or examples of interesting landforms.

The HiWish site itself is helpful here, she points out, because it asks you to categorize your submission according to one of the Mars science themes that MRO is investigating. These include areas such as:

Fluvial Processes – Images of channels, valleys, gullies, or other geologic features likely formed by erosion or deposition by water.Future Exploration/Landing Sites – Attempts to locate known spacecraft, or to provide imagery for upcoming landed missions.Geologic Contacts/Stratigraphy – Images of bedrock exposed within crater central peaks or pits that reveal the stratigraphy at depth, as well as geologic contacts between distinct units/materials that can be used to infer stratigraphic relationships, such as relative ages or processes of deposition.Volcanic Processes - Features produced by molten rock, such as lava flows, ash beds, cinder cones, and volcanoes.

Besides its inherent scientific value, there are other factors in determining which targets are acquired first, such as the current Martian season and what time of day the spacecraft will be passing over the target. The process for selecting and executing an observation can be quite an adventure, and involves a great deal of coordination, skill, and maybe even a little luck between scientists and the teams who fly the spacecraft. (I’ll have more about that, and an insider’s look at exploring Mars with MRO, in a future post.)

Once a target has been selected, things can move pretty fast despite the complexities involved. Although it took a few months to hear back about my HiWish (the time can vary greatly), you’ll notice that the spacecraft actually shot my image less than two months ago, and I’m already poring over every pixel, exploring rock faces, craters, and dune-like ripples. It’s the next best thing to being there.

So, what did I find? My HiWish may not be the most showy HiRISE image ever, but Mars always has something interesting to check out. The context is an ancient river bed near the Martian equator called Verde Vallis, named after a valley in Arizona.

In images from MRO’s context camera, I saw a point where two channels converge. I decided that might be a good place to zoom in, especially since I thought I saw interesting features such as dust devil tracks and the dark slope streaks that often form in equatorial regions. Sure enough, that’s what HiRISE saw:

The entire landscape is coated in dust, which hides some details and paints everything in that typical Martian orange. But there are a few places that are worth examining in more detail. Right in the middle of the channel there are some striking dust ripples and slope streaks.

The floor of Verde Vallis – NASA / JPL / University of Arizona

There appear to be several dark, fresh streaks alongside faded examples from the past. Most streaks like this probably result from dry avalanches, although there are places on Mars where briny water may be seeping out from underground acquifers in the rock. This observation as a whole is shot through with slope streaks, facing almost every direction of the compass. I don’t know if water played a role in any of them, but it’s intriguing to think about. Here are a couple of close-ups from locations on the north side of the channel:

Slope Streak – NASA / JPL / University of Arizona

Slope Streak – NASA / JPL / University of Arizona

There are other places in this little corner of Mars that, besides their scientific potential, are just beautiful in their own way, such as the rhythmic ripples at the top of this post. There’s another spot I like, where dust devils have meandered through the scene, making their own abstract art in the dust.

Streaks and Devils – Contrast-enhanced view of the floor of Verde Vallis, Mars as observed by the HiRISE instrument on board the Mars Reconnaissance Orbiter. The area shown is roughly 200 meters across. NASA / JPL / University of Arizona / Processed by Bill Dunford

I’ll always remember with wonder the time I played a very small role in exploring Mars. Now that I’ve tried it, I’ll be submitting many more HiWishes and crossing my fingers, waiting for word from that most distant desert that there is my own postcard waiting for me and for anyone else who cares to look.

This article originally appeared as a guest post on The Planetary Society site.

I don’t know my last orbit’s number
But when I trace that final curve
I hope I’m like you:
Careening headlong into fresh frontiers
Radiating
A head full of new stories
That I didn’t quite have time
To finish telling

Goldstone – April 19, 2015

I want to be more like Goldstone
Remote from routine radio
From morning shows, sugar spike pop, chronic anger
Away from the fumes of cars pushing through
The bruised vein connecting LA to Vegas
Shielded from the low static of alarm and boredom
I want to be apart from thoughtless days
One following after another like boxcars rattling into Barstow

I want to earn the silence of an open sky
To listen to the desert
The commerce of mice
The glow of scorpions
The slow rumble of rock rising and weathering
To the percussion of summer lightning
The sigh of a cactus flower opening
Just as Jupiter clears the horizon

Even now, pictures of the rings sparkling in Saturn’s cold daybreak
Are arriving on waves that gently wash over my body and yours

I want to be exquisitely sensitive to the subtlest of light
I want to reverberate to the hushed, awed whispers

Drawing: Paul Calle, 1971

Shoemaker-Levy – April 9, 2015

I remember you
From that ancient common swirl
How sweet to be home

For the Same Reason – April 1, 2015

Rendezvous – April 11, 2014

Venus and the Moon as seen in an image from a star-tracker camera on board the Clementine spacecraft. Image: NASA / Naval Research Laboratory | Poem: Bill Dunford